Closure device for multiple injection blow molding machine

ABSTRACT

A closure device for blow molding apparatus having a rotatable turret with parison pins projecting from the face thereof and separable mold halves encompassing the pins to define mold cavities thereabout. A lever interconnects the movable segment of the mold half and a relatively fixed pivot point. The turret is connected to the lever intermediate the pivot point and the mold half to move a fraction of the distance of the mold half such that the pins and molded objects thereon clear the mold halves upon opening thereof for rotation of the turret.

United States Patent Johnson [451 Oct. 10, 1972 CLOSURE DEVICE FORMULTIPLE INJECTION BLOW MOLDING MACHINE Inventor: Joseph A. Johnson,Brigantine, NJ.

Jomar Industries, Inc., Brigantine, NJ.

Filed: Aug. 24, 1970 Appl. No.: 66,442

Assignee:

US. Cl. ..425/ 168, 425/242 Int. Cl. ..B29d 23/03 Field of Search ..18/5BM, 5 BP, 5 BJ, 5 BB, 18/5 BA, 5 BR, 20 B, 2 RM, 2 RP; 74/110; 425/242,168

References Cited UNITED STATES PATENTS De Matteo 18/5 3.!

10/ 1950 Diener ..74/1 10 X 6/1965 Baker et al ..74/l 10 X PrimaryExaminerJ. Spencer Overholser Assistant Examiner-Michael 0. SuttonAttorney-Stowell & Stowell ABSTRACT A closure device for blow moldingapparatus having a rotatable turret with parison pins projecting fromthe face thereof and separable mold halves encompassing the pins todefine mold cavities thereabout. A lever interconnects the movablesegment of the mold half and a relatively fixed pivot point. The turretis connected to the lever intermediate the pivot point and the mold halfto move a fraction of the distance of the mold half such that the pinsand molded objects thereon clear the mold halves upon opening thereoffor rotation of the turret.

3 Claim, 5 Drawing Figures PKTENTEDUBT 10 I 3.697.210

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JOSEPH A. JOHNSON f BY 5% dawy/ ATTORNEY Till i i l 2 Q ll 1 I CgD f LINVENTOR- P'ATENTEDBBI 10 I972 SHEET 3 [IF 3 INVENTOR JOSEPH A. JOHNSONATTORNEY? CLOSURE DEVICE FOR MULTIPLE INJECTION BLOW MOLDING, MACHINEBACKGROUND OF THE INVENTION from plastic materials and more particularlyrelates to I new and novel improvements in a closure device for multiplestation injectionblow molding machines.

2. Description of the Prior Art Injection blow molding machines thatautomatically operate to form a number of hollow articles, such asbottles, from plastic materials are fairly common in the art and inindustrial usage. A machine of the type involved is more fully describedin applicants co-pending application, Ser. No. 52,807, filed July 7,1970. Such a machine has a number of operating stations surrounding ahorizontally disposed elevatable and rotatable turret which has sidefaces carrying distinct sets of parison pins. The turret is surroundedby the angularly placed stations which include parison mold stations,blow mold stations and ejection stations. The turret is indexed from theparison mold stations, to the blow mold stations and then to theejection stations to cause the parison pins to operatively successivelyoccupy such stations with all stations being simultaneously operative.

Each parison mold station is composed of separable mold halves with thebottom halves being fixed and the movable upper halves being carries byrams which clamp the mold halves together about the parison pins. Aninjection unit injects plastic melt into the closed parison molds aroundthe parison pins to a preset pressure after which the parison molds areopened.

The turret is then raised to lift the pins from the bot tom mold halvesand the turret is indexed to bring the parisons to the blow moldstations where the parisons are located in blow molds. With the parisonslocated in the blow molds pressurized air is passed through the parisonpins to inflate the parisons to the configuration and size determined bythe interior shape and size of the blow molds.

On completion of the blow molding, the turret is rotated in the samedirection to bring the parison pins to the ejection stations where theformed articles are removed from the pins.

A problem that has been encountered with such machines lies in theseparation of the halves of the parison or preform molds and theassociated elevation and indexing of the turret carrying the parisonpins. Unfortunately, the mold halves open independently and the turretis lifted independently so that proper clearance for the pins is notalways provided.

SUMMARY OF THE INVENTION present invention is to provide such a machinewith synchronized movements between the parison mold halves and theturret.

" The invention also furnishes a relatively simple, inexpensive andmaintenence free mechanism for synchronizing movements between themovable parison mold half and the turret by providing a leverinterconnection which reduces the movement of the turret to producerequisite clearance of the components.

In a preferred embodiment, the invention provides a synchronizing devicefor movement between a movable mold half and a rotating turret carryingparison pins including actuating means to move the movable mold 0 halfwith respect to the fixed mold half; a lever interconnecting the movablemold half and a relatively fixed pivot point, the turret being connectedto the lever intermediate the movable mold and the pivot point to move afractional distance therewith upon movement of the movable mold half.

These and other attendant advantages will become better understood tothose skilled in the art by reference to the following detaileddescription when viewed in light of the accompanying drawings whereinlike components throughout the figures thereof are indicated by likenumerals and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a blowmolding machine incorporating structure in accordance with theinvention;

FIG. 2 is a front elevational view of the machine of FIG. 1;

FIG. 3 is an enlarged fragmentary view, partly in section, of a portionof the machine as shown in FIG. 2;

FIG. 4 is a further enlarged detail elevational view of a portion of theapparatus shown in FIG. 3; and

FIG. 5 is a sectional view of FIG. 4 taken along the lines 5-5 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT tending parison pins 14 on eachface.

Surrounding the turret are, in counter-clockwise order, a preform orparison mold station 16, a blow mold station 18 and an ejection stationgenerally indicated at 20.

As is more fully described in the aforementioned copending applicationthe mold stations 16 and 18 are provided with horizontally split moldhalves which separate vertically to allow the turret 12 to be raised asseen in FIG."2 and rotated by indexing means (not shown) so that theparison pins are indexed between stations 14, 16 and 18 insequence or inany other manner desired. Although the device in the referred .to

co-pending application is provided with two opposed stations for eachoperation and the cycling is other than straight sequence, the machinemay include less stations, as in the illustrated device, and maybeoperated in an analogous manner to form blow molded objects.

With reference more specifically to FIG. 2 the preform mold station 16includes a lower half parison mold 24 mounted on stationary platen 26and a movable complimentary upper half parison mold 28 mounted on apressure pad 30 attached to the end of a ram or piston rod 32 of ahydraulic cylinder 34 (FIG. 3). When the piston rod 32 is brought downhydraulically the parison mold halves 24 and 28 close about associatedparison pins to define a cavity thereabout. The cavity is then filledwith heated plastic material from an injection unit 29 which is fed tothe cavityfor a set period of time.

The ram 32 operates under a relatively high pressure and, in accordancewith this invention, some of the operating pressure is utilized to raiseand lower theturret 12 thereby providing synchronous movement betweenthe parison mold and the turret; Such movement is important in that, inorder to clear the mold halves 24 and 28 the pins 14 and parisons formedthereon must be raised from thelower half 24 yet cannot be raised thefull distance of movement of the upper half 28 since the pins andparisons must also clear the upper half cavity portions.

Referring now more particularly to FIG. 3, the mechanism for synchronousmovement between the ram 32 and the turret 12 is illustrated in detail.Such mechanism comprises a follower rod 36 mounted on the pressure pad30 and slidably guided parallel to the piston rod 32 by .bearings 38 and40. A lever arm 42 has end 41 pivotally mounted to the extended end of asecondary hydraulic ram 44 via pivot pin 43. The opposite end 45 of thepivot arm 42 is pivotally attached to the followerrod 36 at pivotalconnection 46. Thus, as the pressure pad 30 is moved in a verticaldirection from the mold closed to the mold open positions, the lever arm42 is raised through its pivotal connection 46 to the follower rod 36and in so moving the rod 42 pivots about pivot pin 43 carried at theextended end of the piston rod of hydraulic ram 44.

The turret 12 is connected to a vertical actuator shaft 48 which servesto provide means to raise or lower the turret as necessary. As can beseen, the shaft 48 is connected to the lever 42 proximate themid-portion thereof such that movement of the turret 48 is approximatelyone-half the movement of the ram 32 thereby providing the requisitesynchronous movement between the turret 12 and the mold halves 24 and 28to allow rotation of the turret in the operation of the machine.

With particular reference to FIGS. 4 and 5, a connection between theshaft 48 and the lever arm 42 is shown. Since any single point on thelever arm 42 follows an arcuate path upon movement of the arm, someprovision must be made for lateral movement of the connection betweenthe lever arm and the shaft. Such connection comprises a slot 50 formedacross the shaft 48 and a roller 52 rotatably mounted on the lever arm42 and disposed to ride in the slot 50. Upon movement of the lever arm42. the roller is displaced along the slot pressure pad 30 whilemaintaining the turret 12 in a lowered position, a capability which canbe of importance if, for example, the position of the parison pins 14 inthe lower mold half needs to be examined. If

the cylinder 44 is actuated to extend simultaneously with retraction ofthe pressure pad 30, the lever arm will pivot about the roller 52 in theslot 50 and the turret 12 will remain, in place. The cylinder 44 ispivotally mounted at its upper end via pivot pin 54 so that lateralmotion between that cylinder and the ram 32 upon movement of the leverarm 42 will be accommodated thereby.

A limit switch 56 is disposed above the ram end of the lever arm 42 andis connected to the cylinder 34 to interrupt operation thereof when thatend of the lever arm is lifted to actuate the. switch. A second limitswitch 58 is disposed above the secondary hydraulic cylinder end of thearm 42 and is connnected to the secondaryhydraulic cylinder 44 tointerrupt operation thereof when that end of the arm is raisedto actuatethe switch.

The turret 12 is supported by a rotatable shaft assembly 62 which has anelectric motor 64 to index the turret between stations. 7

When the mold halves are opened, the turret 12 is next indexed to placethe pins 14 carrying the parisons at the blow mold station 18, whereuponthe blow mold halves are closed about the parisons which are thenexpanded to assume the form and size of the interior of the molds by airunder pressure through the parison pins.

After separation of the blow mold halves, the turret 12 is then indexedagain to place the molded articles at the ejection station 20 forstripping by means such as is described in greater detail in applicantsco-pending application entitled Stripper For Blow Molding Machine filedeven date herewith. After stripping, the cycle is repeated. The parisonpins 14 on the remaining faces of the turret are, of course, indexed atadjacent stations so that for each of the above described cycles, theother phases of the formation are simultaneously being carried out.

Although a machine operating as described above is preferred, it shouldbe understood that this invention may be incorporated in any blowmolding machine from which plural articles formed on parison pins mustbe stripped. I

What has been set forth above is intended as exemplary to enable thoseskilled in the art to practice the invention.

What is new and desired to be protected by Letters Patent of the UnitedStatesis:

1. In a blow molding apparatus having an indexable turret with parisonpins projecting outwardly from the face thereof and separable movableand fixed mold halves closing about said pins to define mold cavitiesthereabout the improvement comprising a turret-mold synchronizing deviceincluding actuating means to move said movable mold half with respect tosaid fixed mold half, and lever means interconnecting said movable moldhalf and said turret to simultaneously move said turret with saidmovable mold half such that said pins and articles formed thereon aredisposedin cavities defined by said mold halves when together and clearof said mold halves for indexing of said turret when said mold halvesare apart, said lever means extending between a normally fixed pivotpoint and said actuating means to move about said actuatingmeans andsaid turret being connected to said lever means intermediate said pivotand said actuating means such that said turret moves a fraction of thedistance of said actuating means upon operation thereof.

distance of said actuating means.

3. A device in accordance with claim 2 wherein a second actuating meanssupports said normally fixed pivot point, said second actuating meansbeing actuable a distance equal and opposite to said first mentionedactuating means to thereby provide for raising of said movable mold halfwithout movement of said turret.

1. In a blow molding apparatus having an indexable turret with parisonpins projecting outwardly from the face thereof and separable movableand fixed mold halves closing about said pins to define mold cavitiesthereabout the improvement comprising a turret-mold synchronizing deviceincluding actuating means to move said movable mold half with respect tosaid fixed mold half, and lever means interconnecting said movable moldhalf and said turret to simultaneously move said turret with saidmovable mold half such that said pins and articles formed thereon aredisposed in cavities defined by said mold halves when together and clearof said mold halves for indexing of said turret when said mold halvesare apart, said lever means extending between a normally fixed pivotpoint and said actuating means to move about said actuating means andsaid turret being connected to said lever means intermediate said pivotand said actuating means such that said turret moves a fraction of thedistance of said actuating means upon operation thereof.
 2. A device inaccordance with claim 1 wherein said turret is connected to said levermeans substantially midway between said pivot and said actuating meanssuch that said turret moves approximately one-half the distance of saidactuating means.
 3. A device in accordance with claim 2 wherein a secondactuating means supports said normally fixed pivot point, said secondactuating means being actuable a distance equal and opposite to saidfirst mentioned actuating means to thereby provide for raising of saidmovable mold half without movement of said turret.